The battle between wood and concrete construction

Founder and CEO , SVN Rock Advisors Inc.
  • Aug. 26, 2019

New construction techniques promise changes to the development industry, but materials interests should not be afraid.

When it comes to building mid-rise, multi-family residential buildings, there’s a new kid in town. Wood-frame construction is already shaking up the development industry, prompting people behind the traditional ways of doing things to warn against embracing the new construction technique just yet.

Is wood the new super-material that will take the purpose-built rental apartment industry into the future? Or are we unwise to throw out the old ways with the bathwater?

A concrete foundation

The traditional method of building multi-family residential buildings is with concrete, the modern form of which was patented in 1824 as Portland cement. This material was used in building construction as early as 1854.

As the material advanced its flexibility, durability and strength led to the first concrete high-rise building being built in Cincinnati in 1904. As skyscrapers started rising on the skylines of cities through the 20th century, concrete as well as steel led the upward charge.

As a building material, wood was around centuries before concrete. It was easy to obtain, versatile and lightweight, an ideal building material for single-family homes and other small buildings.

As urban development from the 1950s onward polarized between low-density suburban housing subdivisions and high-rise apartment towers, wood and concrete each staked their territory. The line between the two wasn’t blurred until the early part of the 21st century.

The rise of mid-rise wood

Around the year 2000, new construction techniques and new lumber products started to make wood a useful construction material in larger buildings. At the same time, cities across North America moved away from the modern suburban-style development toward a more diversified urban fabric.

City planners wanted to encourage pedestrian-friendly streets with increased densities, and while high-rises offered higher densities, extremely tall buildings might not be appropriate for a particular urban environment, or the core of a small town.

Instead, to increase densities along suburban arterial roads, many cities looked to mid-rise residential and commercial buildings to provide higher densities with pedestrian- and transit-friendly environments.

Here, wood had a decided advantage in the new build form.

Concrete and steel were appropriate for high-rise construction, but were expensive. Building mid-rise buildings out of concrete and steel was less cost-effective. Wood was lighter, which made it cheaper to transport and build with.

Mid-rise buildings built out of wood could be more profitable for developers than ones built out of concrete and steel.

Wood transforms the industry

In 2009, British Columbia changed its building codes to allow wood-frame construction for buildings up to six storeys tall. Since then, more than 300 mid-rise wood-framed buildings have been built or are under construction in the province.

Quebec, Ontario and Alberta also changed their building regulations to allow for six-storey wood around 2013 and, in 2015, the National Building Code of Canada permitted wood-frame construction for six-storey residential and commercial buildings.

The United States has followed this trend as well.

Recently, the developer of North Tract Lofts in Arlington, Va., changed its building plans from concrete to wood frame construction. The developer said the move could shave 40 per cent from the construction cost of the project.

Another example is the WREN multi-family project in the South Park district of Los Angeles. The $144-million development features seven-storey buildings made out of wood that conform to California’s strict earthquake-resistant construction regulations.

Concrete and steel push back

The push for wood has been enthusiastically supported by lumber and forestry interests across North America.

The concrete and steel industries, fearing the loss of market share, have fired back, questioning the wisdom of changing the building codes, and questioning the safety and environmental sensitivity of wood as a construction material for mid-rise buildings.

Those concerns were amplified when a wood-frame five-storey, 241-unit building under construction in downtown Raleigh, N.C., caught fire and burned to the ground.

The American National Ready Mixed Concrete Association created a coalition called Build with Strength, with a mandate “to educate the building and design communities and policymakers on the advantages of ready mixed concrete and encourage its use as the building material of choice for low-to-mid-rise structures.”

Spokesman Kevin Lawlor said: “What a lot of folks in the NRMCA saw was wood products and combustible materials becoming a product of choice in the low-to-mid-rise residential construction market, and knowing that they had a safer, more durable product, wanted to do something about promoting the product in the space so that we could convince more people to build with concrete for all the benefits that it brings to the table.”

Perceptions to overcome

As a new construction technique, wood needs to overcome a number of preconceptions, and prove itself on a number of issues.

A study conducted by GLOBE Advisors for the Concrete Council of Canada noted that insurance premiums for wood-framed buildings were six times higher than comparable concrete buildings. The study cited four major concerns to justify the higher rates:

* greater fire peril;

* significantly higher moisture risk resulting in potential mould and mildew contamination;

* the ability of wood-frame buildings to handle severe weather including storms brought about by climate change;

* and “difficulty in obtaining insurance for wood-frame structures.”

That last concern is clearly a self-fulfilling prophecy, since citing the difficulty of wood-frame buildings in obtaining insurance itself increases the difficulty of obtaining insurance.

However, Len Garis, the chief of the Surrey Fire Department in British Columbia downplayed the safety concerns, saying, “The safety level of buildings, once completed and equipped with the required protection systems under the building code, would be equivalent to that of any similar building constructed with other materials.”

The building that burned down in Raleigh, it was noted, did so when it was under construction and at a phase that most buildings, regardless of their construction materials, are at their most vulnerable.

How green is wood?

Wood also has some perception issues to overcome when it comes to its environmental footprint, given the controversy the forestry industry sometimes faces.

However, proponents of wood note the North American forestry industry is increasingly following sustainable practises when harvesting wood and wood’s environmental impact becomes more favourable when considering the environmental impact of steel and concrete.

Concrete, for instance, is typically made up of 60-75 per cent aggregate, and 15-20 per cent water. Aggregate has to be removed from the ground in quarries and doesn’t grow back.

The manufacturing process requires energy and produces pollution.

Steel is made from iron that has to be mined and then smelted in blast furnaces that reach over 1,600 degrees C, again requiring considerable fuel and adding to steel’s carbon footprint.

By comparison, wood absorbs carbon dioxide before it is harvested, removing it from the atmosphere.

Unlike aggregate or iron, or the fuel used to produce them, wood is a renewable resource. Many North American sawmills are even using woody biomass rather than fossil fuels to fuel their operations.

A place for every material

If wood-frame buildings are as safe as buildings made of concrete and steel, then it’s only a matter of time before developers come to understand the benefits as well as the risks associated with the new mid-rise construction method.

As the insurance companies get more data on wood-frame buildings operating safely, they will lower their risk assessments and insurance premiums will drop.

It is unfortunate seeing interest groups of various construction materials square off in this fashion. Wood has a big part to play in the changing landscape of urban form. It offers a construction technique that will save developers money and will be easier on the environment.

Yes, some questions remain, but the research on wood as a mid-rise construction material is continuing.

Officials at LP Building Products and the Network for Earthquake Engineering and Simulation organized an upcoming shake test on a seven-storey tall, 23-unit condominium tower made from LP’s wooden I-Joists and its SolidStart Laminated Veneer Lumber.

Weighing more than a million pounds, this shake test will be the world’s largest, and officials from the U.S. and Canadian governments will be in attendance, watching with interest.

Concrete and steel interests should not be afraid about losing market share to wood. There will continue to be a need for high-rise construction, and technological advances in concrete construction, including 3D printing of concrete forms, will increase the role concrete has to play at all levels in the development industry.

The key is to innovate, rather than stifle innovation.

Wood, concrete, and steel will continue to be vital components in the development industry to come, but developers now have more and better tools with which to build their buildings. As it gets cheaper to build, more and better buildings will be built, which will benefit all.

 

SVN Rock Advisors Inc., Brokerage is an Ontario-based commercial real estate, consulting and new construction lease-up company with an exclusive focus on the apartment sector. We are a boutique brokerage firm that specializes in multi-residential properties (apartments). Our specialty is in delivering institutional quality services to private capital owners and investors while representing buyers and sellers of apartment properties in the transaction process. With this exclusive focus on apartments, we have developed world class systems and processes that allow us to handle every type of apartment transaction with efficiency.


Derek Lobo is the Broker of Record and CEO of SVN Rock Advisors Inc., Brokerage. Derek is regarded as a ‘thought leader’ in the apartment & student housing industries, specializing…

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Derek Lobo is the Broker of Record and CEO of SVN Rock Advisors Inc., Brokerage. Derek is regarded as a ‘thought leader’ in the apartment & student housing industries, specializing…

Read more





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